Structural, optical, mechanical, and electronic properties of Cr-doped alumina

Cr-doped α-Al2O3 samples (Al2−xCrxO3, 0 ≤ x ≤ 0.25; step 0.05) were synthesized by citrate-precursor autocombustion method. The lattice parameters, bond distortion index, crystallite size, and lattice microstrain of the developed system were investigated using Rietveld profile method. The porous nature of the formed samples was elucidated by a scanning electron microscope. The effect of doping on the vibrational band positions was examined using Fourier-transform infrared technique. The photoluminescence emission showed that a red color was mainly exhibited by all samples, while that with x = 0.05 showed the highest intensity. Other colors appear with a small intensity for higher Cr-doped samples. The electronic, optical, and mechanical stability properties of undoped and doped samples were investigated using density-functional theory calculation.